Field of the Invention
The present invention relates to a wafer processing method for dividing a wafer along a plurality of division lines, the front side of the wafer being partitioned by the division lines to define a plurality of separate regions where a plurality of devices are formed.
Description of the Related Art
There is disclosed in Japanese Patent Laid-open No. 2014-221483 a method of dividing a wafer along a plurality of division lines, the front side of the wafer being partitioned by the division lines to define a plurality of separate regions where a plurality of devices such as integrated circuits (ICs), large-scale integrations (LSIs), and light-emitting diodes (LEDs) are formed. In this method, the wafer is first attached to an adhesive tape fixed at its peripheral portion to a frame, thereby supporting the wafer through the adhesive tape to the frame. Thereafter, a pulsed laser beam having a transmission wavelength to the wafer is applied along each division line in the condition where the focal point of the pulsed laser beam is set inside the wafer, thereby forming a strength reduced portion along each division line. Thereafter, a radial tension is applied to the adhesive tape attached to the wafer, thereby dividing the wafer along the division lines to obtain individual device chips.